A computer network is a collection of interconnected computing devices that can exchange data and share resources. A physical connection between devices within the network is generally referred to as a link. In a packet-switching network, such as an Ethernet network, network devices that provide the network infrastructure communicate data by dividing the data into variable-length blocks called packets, which are individually routed across the network from a source device to a destination device. The destination device extracts the data from the packets and assembles the data into its original form. The intermediate network devices that perform packet switching, such as high-speed routers or network switches, often have internal switch fabrics that are engineered specifically for the demands of high-speed packet switching.
In some cases, a high-speed network device may include packet forwarding engines interconnected by a switch fabric, where that each received packet is segmented into fixed-size fabric cells that are transmitted over the internal switch fabric between the packet forwarding engines. The packet forwarding engines segment inbound packets into the fabric cells that are input into the internal switch fabric, and reassemble packets from the fabric to form outbound packets to be output to next hops within the network. Internal packet queues maintained within the packet forwarding engines may cause varying packet transfer delay within the network, and such delay is tolerated and managed by the sending and receiving device as well as the intermediate routers and other devices of the packet-switching network.